Drive guide device

ABSTRACT

The present invention provides a drive guide apparatus capable of ensuring an increased lifetime by preventing heat generated from a primary side of a linear motor from being transferred to a rail or a moving member of a guide mechanism to which the primary side of the linear motor is connected, thereby preventing variation of rolling resistance or sliding resistance of the guide mechanism. The drive guide apparatus has a linear motor and a guide mechanism that has a rail and a moving member provided to be movable relative to the rail. A primary side of the linear motor is connected to the rail. Thermal for blocking heat generated from the primary side of the linear motor are provided between the primary side and the rail of the guide mechanism to which the primary side is connected directly or indirectly.

TECHNICAL FIELD

The present invention relates to a drive guide apparatus that has aguide mechanism including a rail and a moving member provided to bemovable relative to the rail and that uses a linear motor as a drivingmeans.

BACKGROUND ART

Conventional drive guide apparatuses of this type are disclosed inJapanese Patent Post-Exam Publication No. Hei 7-106053 and JapanesePatent Application Unexamined Publication (KOKAI) No. 2001-99151. FIG. 1is a diagram showing schematically the arrangement of a conventionaldrive guide apparatus of the type described above.

In the figure, a linear motor 100 comprises a primary side 101 and asecondary side 102. The primary side 101 is an energized side includingarmature coils. The secondary side 102 is a non-energized side havingmagnets, etc. The primary side 101 is connected through a table 103 tomoving blocks 105 each serving as a moving member of a guide mechanism104. The secondary side 102 of the linear motor 100 is secured to a base106. The base 106 is secured to the top of a surface plate 107.

The base 106 is provided thereon with two parallel rails 108constituting the guide mechanism in combination with the moving blocks105. The moving blocks 105 move along the rails 108 in response todriving force obtained from the linear motor 100.

The rails 108 are each formed with a plurality of rolling elementrolling surfaces extending longitudinally, as will be detailed later.The moving blocks 105 are each formed with endless recirculationpassages including load rolling element rolling passages correspondingto the rolling element rolling surfaces. When the moving blocks 105 movealong the rails 108, a plurality of rolling elements arranged andaccommodated in the endless recirculation passages roll and recirculatewhile receiving a load in the load rolling element rolling passages.

In the drive guide apparatus arranged as stated above, the table 103secured to the moving blocks 105 to extend therebetween is provided withthe primary side 101 of the linear motor 100, which is the energizedside including armature coils. Therefore, when a driving electriccurrent is passed through the armature coils (not shown) of the primaryside 101, heat generated from the primary side 101 is transferred to thetable 103, causing the table 103 and the moving blocks 105 to be heatedto expand. Consequently, stress due to the thermal expansion of thetable 103 and the moving blocks 105 is applied to the moving blocks 105.

The rolling elements arranged and accommodated in the endlessrecirculation passages of the moving blocks 105 constituting the guidemechanism 104 have been given a predetermined preload. Morespecifically, rolling elements having a diameter slightly larger thanthe diameter of the load rolling element rolling passages are insertedinto the rolling passages, thereby producing a negative clearance, i.e.causing the rolling elements and the rolling surfaces to be elasticallydeformed.

When stress due to thermal expansion is applied to the moving blocks 105as stated above, the preload is varied. That is, the preload increasesat one side and decreases or becomes zero at the other side. Theincrease in the preload involves the problem that the rolling resistanceto the rolling elements increases, leading to shortening of the lifetimeof the drive guide apparatus.

Here, let us explain the preload. The preload is applied in order toensure a predetermined rigidity adequate for each particular purpose. Inapparatus that are required to exhibit high accuracy, e.g. precisionmeasuring apparatus, a light preload necessary for removing play isapplied because the apparatus cannot perform the desired function ifthere is play. In machine tools or the like, an intermediate preload isapplied in order to ensure the required rigidity because a cuttingoperation and the like cannot be performed unless the rigidity issufficiently high.

It should be noted that rigidity includes static rigidity and dynamicrigidity. Static rigidity is the ability to resist a static load, i.e. adisplacement of the moving block relative to the mounting referenceplane. Dynamic rigidity is performance required for machine tools, forexample, which is expressed by the reciprocal ratio of the deflectionwidth of a time-varying displacement to the deflection width of atime-varying load. In short, dynamic rigidity is the ability to minimizeexternal vibration transmission. That is, insufficient dynamic rigidityof a machine tool, for example, causes chatter during cutting or othermachining process and leads to a problem that the machine tool isreadily affected by external vibration.

The above-described conventional example has a rolling guide arrangementin which the moving blocks 105 each serving as a moving member areengaged with the rails 108 through rolling elements. It should be noted,however, that the above-described problems also occur in the case ofemploying a slide guide arrangement in which rolling elements are notinterposed between a rail and a moving member. In this case also, thelifetime of the guide apparatus is shortened.

In the rolling guide, an increase in rolling resistance gives rise to aproblem. In the case of slide guide, an increase in sliding resistancebecomes a problem.

The present invention was made in view of the above-describedcircumstances. An object of the present invention is to provide a driveguide apparatus capable of ensuring an increased lifetime by preventingheat generated from a primary side of a linear motor from beingtransferred to a rail or a moving member of a guide mechanism to whichthe primary side of the linear motor is connected, thereby preventingvariation of rolling resistance of the guide mechanism (when arranged inthe form of a rolling guide) or sliding resistance of the guidemechanism (when arranged in the form of a slide guide).

DISCLOSURE OF THE INVENTION

To attain the above-described object, the present invention provides adrive guide apparatus having a linear motor and a guide mechanism thatguides relative movement between a primary side of the linear motor,which is an energized side thereof, and a secondary side of the linearmotor, which is a non-energized side thereof, and that carries a load.The guide mechanism has a rail and a moving member provided to bemovable relative to the rail. The primary side of the linear motor isconnected directly or indirectly to the rail or the moving member of theguide mechanism. Thermal insulating means for blocking heat generatedfrom the primary side of the linear motor is provided between theprimary side of the linear motor and the rail or the moving member ofthe guide mechanism to which the primary side of the linear motor isconnected.

As stated above, thermal insulating means for blocking heat generatedfrom the primary side of the linear motor is provided between theprimary side of the linear motor and the rail or the moving member ofthe guide mechanism to which the primary side of the linear motor isconnected directly or indirectly. Therefore, the heat transfer cutoffaction of the thermal insulating means prevents heat generated from theprimary side of the linear motor from being transferred to the rail orthe moving member of the guide mechanism. Consequently, thermalexpansion of the rail or the moving member is prevented, and there is novariation in rolling resistance or sliding resistance of the guidemechanism. Accordingly, it is possible to ensure an increased lifetimefor the drive guide apparatus.

In the drive guide apparatus, the thermal insulating means may comprisea thermal insulator interposed between the rail or the moving member andthe primary side of the linear motor.

If the thermal insulating means comprises a thermal insulator interposedbetween the rail or the moving member and the primary side of the linearmotor, as stated above, an increased lifetime can be ensured for thedrive guide apparatus with a simple arrangement.

In the drive guide apparatus, the thermal insulator may be elongated inthe direction of relative movement between the rail and the movingmember.

If the thermal insulator is elongated in the direction of relativemovement between the rail and the moving member, as stated above,rigidity in this direction increases. Thus, undesired oscillationphenomena can be prevented.

In the drive guide apparatus, the thermal insulating means may comprisea thermal insulating space formed between the rail or the moving memberand the primary side of the linear motor.

If the thermal insulating means comprises a thermal insulating spaceformed between the rail or the moving member and the primary side of thelinear motor, as stated above, it is possible to cut off the transfer ofradiation heat from the primary side of the linear motor. Therefore, itis possible to prevent thermal expansion of the rail or the movingmember due to radiation heat and hence possible to eliminate variationin rolling resistance or sliding resistance of the guide mechanism.Accordingly, an increased lifetime can be ensured for the drive guideapparatus as in the case of the above.

In the drive guide apparatus, the thermal insulating space may have amirror finished surface at a side thereof closer to the rail or themoving member of the guide mechanism to which the primary side of thelinear motor is connected.

If the thermal insulating space has a mirror finished surface at a sidethereof closer to the rail or the moving member of the guide mechanismto which the primary side of the linear motor is connected, as statedabove, the transfer of radiation heat from the primary side of thelinear motor can be cut off even more effectively.

The drive guide apparatus may also be arranged as follows. The rail isformed with a rolling element rolling surface extending longitudinallyof the rail. The moving member has an endless recirculation passageincluding a load rolling element rolling passage corresponding to therolling element rolling surface. A multiplicity of rolling elements arearranged and accommodated in the endless recirculation passage. Therolling elements recirculate through the endless recirculation passagewhile receiving a load in the load rolling element rolling passage.

With the above-described arrangement, the preload applied to the rollingelements is not varied by a stress generated by thermal expansion of therail or the moving member. Accordingly, smooth rolling of the rollingelements is ensured, so that an increased lifetime of the drive guideapparatus is attained. In the rolling guide, if the preload increases,flaking (a phenomenon in which the surface of the raceway surface or therolling element surface peels off in flakes owing to the rolling fatigueof the material) is likely to occur. If flaking occurs, the lifetimereduces markedly. In the slide guide, such a flaking problem is unlikelyto occur.

The drive guide apparatus may be provided with a heatsink thatdissipates heat generated from the primary side of the linear motor.

If a heatsink is provided to dissipate heat generated from the primaryside of the linear motor, as stated above, heat generated from theprimary side of the linear motor can be dissipated efficiently.Therefore, the transfer of the heat to the rail or the moving member ofthe guide mechanism is further retarded. As a result, restrictions onthe linear motor configuration for heat dissipation are reduced.Accordingly, it is possible to employ a linear motor having anarrangement even more suitable for the drive guide apparatus.

In the drive guide apparatus, the heatsink may be a finned heatsinkhaving radiating fins.

If a finned heatsink having radiating fins is used, as stated above, theheat dissipation effect is further enhanced. Accordingly, the transferof heat to the rail or the moving member of the guide mechanism isfurther retarded.

In addition, the present invention provides a drive guide apparatushaving a linear motor and a guide mechanism that guides relativemovement between a primary side of the linear motor, which is anenergized side thereof, and a secondary side of the linear motor, whichis a non-energized side thereof, and that carries a load. The guidemechanism has a rail and a moving member provided to be movable relativeto the rail. The primary side of the linear motor is connected to themoving member through a heatsink, and an absorbing member is provided atthe joint between the primary side of the linear motor and the movingmember. The absorbing member absorbs a deformation of the heatsink dueto a thermal expansion difference between the moving member and theheatsink by shearing force deformation.

In the above-described arrangement, a deformation absorbing member isprovided at the joint between the moving member and the heatsink. Thus,when the heatsink is thermally expanded and deformed by heat from theprimary side of the linear motor, shearing force acts on the absorbingmember. Consequently, the absorbing member is shear-deformed to absorbthe deformation of the heatsink. Therefore, no stress is applied to theheatsink, and hence the heatsink is not deformed. There is also nodisplacement of the primary side of the linear motor that is attached tothe heatsink. Accordingly, there is no change in the gap between theprimary side and the secondary side of the linear motor. Hence, there isno change in characteristics of the linear motor.

In the drive guide apparatus, the absorbing member may have both thefunction of absorbing a deformation of the heatsink by shear deformationand the thermal insulating function of cutting off the heat transferfrom the heatsink to the moving member.

With the above-described arrangement, the absorbing member has both thefunction of absorbing a deformation of the heatsink by shear deformationand the thermal insulating function of cutting off the heat transferfrom the heatsink to the moving member. Therefore, no influence isexerted upon the characteristics of the linear motor as stated above.Moreover, there is no variation in rolling resistance or slidingresistance of the guide mechanism.

In the drive guide apparatus, the absorbing member may be a laminatedglass-epoxy resin material.

If a laminated glass-epoxy resin material is used for the absorbingmember, as stated above, a deformation of the heatsink is absorbedeasily. That is, the laminated glass-epoxy resin material exhibitsstrong rigidity in the lamination direction (thickness direction) andweak rigidity in a direction (width direction) perpendicular to thelamination direction. Therefore, when the heatsink thermally expands inresponse to a rise in temperature, shearing force acts on the absorbingmember. At this time, the absorbing member is easily deformed to absorbthe deformation of the heatsink.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing schematically the arrangement of aconventional drive guide apparatus.

FIG. 2 is a diagram showing schematically a structural example of thedrive guide apparatus according to the present invention.

FIG. 3 is a diagram showing schematically a structural example of thedrive guide apparatus according to the present invention.

FIG. 4 is a plan view showing a structural example of the drive guideapparatus according to the present invention.

FIG. 5 is a side view showing a structural example of the drive guideapparatus according to the present invention.

FIG. 6 is a view as seen in the direction of the arrow A-A in FIG. 5.

FIG. 7 is a view as seen in the direction of the arrow B-B in FIG. 5.

FIG. 8 is a perspective view showing a structural example of a guidemechanism of the drive guide apparatus according to the presentinvention.

FIG. 9 is a sectional view showing a structural example of the guidemechanism of the drive guide apparatus according to the presentinvention.

FIG. 10 is a sectional view showing a structural example of a movingblock in the guide mechanism of the drive guide apparatus according tothe present invention.

FIG. 11 is a diagram showing schematically a structural example ofanother embodiment of the drive guide apparatus according to the presentinvention.

FIG. 12 is a perspective view showing a structural example of a guidemechanism of the drive guide apparatus according to the presentinvention.

FIG. 13 is a diagram showing schematically a structural example of stillanother embodiment of the drive guide apparatus according to the presentinvention.

FIG. 14 is a diagram showing schematically a structural example of adrive guide apparatus having a slide guide mechanism according to thepresent invention.

FIG. 15 is a diagram showing schematically a structural example ofanother drive guide apparatus having a slide guide mechanism accordingto the present invention.

FIG. 16 is a diagram showing schematically a structural example of stillanother drive guide apparatus having a slide guide mechanism accordingto the present invention.

FIG. 17 is a graph showing exemplarily the result of a temperature-risetest performed on the drive guide apparatus according to the presentinvention.

FIG. 18 is a graph showing exemplarily the result of a temperature-risetest performed on the drive guide apparatus according to the presentinvention.

FIG. 19 is a graph showing exemplarily the result of a temperature-risetest performed on the drive guide apparatus according to the presentinvention.

FIG. 20 is a graph showing exemplarily the result of a temperature-risetest performed on the drive guide apparatus according to the presentinvention.

FIG. 21 is a diagram showing schematically a structural example of thedrive guide apparatus according to the present invention.

FIG. 22 is a diagram showing a structural example of the drive guideapparatus according to the present invention.

FIG. 23 is a diagram showing the arrangement of a radiating fin plate ofa finned heatsink of the drive guide apparatus shown in FIG. 22.

FIG. 24 is a diagram showing the arrangement of a radiating fin of theradiating fin plate shown in FIG. 23.

FIG. 25 is a diagram showing a structural example of the drive guideapparatus according to the present invention.

FIG. 26 is a diagram showing the relationship between the table and theheatsink that varies in response to a temperature rise in the driveguide apparatus according to the present invention.

FIG. 27 is a diagram for explaining the deformation of a thermalinsulator.

FIG. 28 is a diagram showing the joint structure of the table and theheatsink in the drive guide apparatus according to the presentinvention.

FIG. 29 is a diagram for explaining the deformation of a flangedcylindrical member.

FIG. 30 is a diagram showing a structural example of the heatsink.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 2 is a diagram showing schematically a structural example of afirst embodiment of the drive guide apparatus according to the presentinvention. In the figure, a linear motor 10 comprises a primary side 11and a secondary side 12. The primary side 11 is an energized sideincluding armature coils. The secondary side 12 is a non-energized sidehaving magnets, etc. The primary side 11 is connected through a table 13to moving blocks 15 each serving as a moving member of a guide mechanism14. The secondary side 12 of the linear motor 10 is secured to a base16. The base 16 is secured to the top of a surface plate 17. In thisregard, the drive guide apparatus according to the present invention isthe same as the conventional example shown in FIG. 1.

The base 16 is provided thereon with two parallel rails 18 constitutingthe guide mechanism in combination with the moving blocks 15. The movingblocks 15 move along the rails 18 in response to driving force obtainedfrom the linear motor 10. In this regard also, the drive guide apparatusaccording to the present invention is the same as the conventionalexample shown in FIG. 1.

The drive guide apparatus according to the present invention differsfrom the drive guide apparatus shown in FIG. 1 in that a thermalinsulator 19 is provided between the primary side 11 of the linear motor10 and the table 13 to prevent heat generated from the primary side 11from being transferred to the table 13. As a material for the thermalinsulator 19, a glass-filled epoxy resin material, a ceramic material,etc. are usable.

With the above-described arrangement in which the thermal insulator 19is provided between the primary side 11 of the linear motor 10 and thetable 13, heat generated from the armature coils (not shown) of theprimary side 11 when a driving electric current is passed therethroughis prevented from being transferred to the table 13 or the moving blocks15. Therefore, thermal expansion of the table 13 or the moving blocks 15does not occur.

Accordingly, there is no variation in preload (contact pressure) appliedto a plurality of rolling elements, e.g. balls, arranged andaccommodated in the endless recirculation passages of the moving blocks15 of the guide mechanism 14, and the rolling resistance can be keptconstant. Therefore, an increased lifetime can be ensured for the driveguide apparatus.

In the drive guide apparatus arranged as stated above, the thermalinsulator 19 is provided over the whole surface of the primary side 11of the linear motor 10, by way of example. However, the arrangement maybe such that the thermal insulator 19 is not provided over the wholesurface of the primary side 11 but positioned at a predetermined regionon each side of the primary side 11 in such a manner as to extendlongitudinally of the rails 18 as shown, for example, in FIG. 3.

If a recess 20 acting as a thermal insulating space is provided on thelower side of the table 13 at a position between the thermal insulators19, it becomes possible to cut off the transfer of radiation heat fromthe primary side 11.

In the above-described example, both the thermal insulator 19 and therecess 20 serving as a thermal insulating space are provided. By doingso, the thermal insulating effect is improved more than in the case ofemploying either of them. However, the required thermal insulatingeffect can be ensured by using only either of them.

If the surface of the table 13 that faces the recess 20 serving as athermal insulating space (i.e. the inner surface of the recess 20) isformed into a mirror finished surface, the transfer of radiation heatcan be cut off even more effectively. It should be noted that the mirrorfinished surface is obtained by electroless nickel plating, polishing,etc.

In addition, if the thermal insulator 19 is elongated in thelongitudinal direction of the rails 18, that is, in the direction ofmovement of the table 13 (moving blocks 15), rigidity in this directionincreases. Thus, undesired oscillation phenomena can be prevented.

Next, a specific structural example of the drive guide apparatusaccording to the present invention will be described. FIGS. 4 to 7 showa structural example of the drive guide apparatus according to thepresent invention. FIG. 4 is a plan view. FIG. 5 is a side view. FIG. 6is a view as seen in the direction of the arrow A-A in FIG. 5. FIG. 7 isa view as seen in the direction of the arrow B-B in FIG. 5. In FIGS. 4to 7, the same reference numerals as those in FIGS. 2 and 3 denote thesame or corresponding portions.

The primary side 11 of the linear motor 10 comprises armature coils andarmature cores. The secondary side 12 of the linear motor 10 comprises amagnet plate. The secondary side 12 is secured to the base 16.

As shown in FIG. 7, thermal insulators 19 made of a glass-epoxy resinare provided between the primary side 11 of the linear motor 10 and thetable 13 to prevent heat generated from the primary side 11 from beingtransferred to the table 13.

The thermal insulators 19 are disposed on both sides of the primary side11 and elongated in the longitudinal direction of the rails 18. A recess20 serving as a thermal insulating space is formed on the lower side ofthe table 13 at a position between the thermal insulators 19. Thesurface of the table 13 that faces the thermal insulating space (i.e.the inner surface of the recess 20) is formed into a mirror finishedsurface.

The rails 18 are disposed (secured) on the base 16 in parallel to eachother at both sides of the secondary side 12 of the linear motor 10,which comprises a magnet plate. The rails 18 each have a plurality (twoin the illustrated example) of moving blocks 15 provided thereon in sucha manner as to be movable along the associated rail 18. The table 13 issupported by a plurality (four in the illustrated example) of movingblocks 15 movably provided on the rails 18.

When a driving electric current is passed through the armature coils(not shown) of the primary side 11 of the linear motor 10, the primaryside 11 moves along the secondary side 12 in response to a magneticinteraction between the primary side 11 and the secondary side 12. Theforce of movement of the primary side 11 is transmitted to the movingblocks 15 through the table 13, causing the moving blocks 15 to movealong the rails 18.

End plates 21 are installed on both end portions of the base 16.Stoppers 22 are mounted on the end plates 21, respectively. Scrapers 23are attached to both ends of the table 13.

A linear scale 24 is provided on one side portion of the base 16. Alinear encoder head 25 is attached to one side portion of the table 13through a bracket 26 to read the linear scale 24 to thereby detect thetravel position (travel distance) of the table 13.

A cable bear mount plate 27 is secured to the other side portion of thebase 16. A cable bear socket 28 is secured to the other side portion ofthe table 13.

On the cable bear mount plate 27 are disposed a power cable 29 forsupplying driving electric power to the primary side 11 of the linearmotor 10, a signal cable 30 for transmission and reception of signals,and nylon tubes 31 for supplying water or the like to cool the primaryside 11. The power cable 29, the signal cable 30 and the nylon tubes 31are connected to the primary side 11 of the linear motor 10 through thecable bear socket 28.

It should be noted that reference numeral 38 in the figures denotes acenter cover, and reference numeral 39 denotes side covers.

As has been stated above, the thermal insulators 19 are provided betweenthe primary side 11 of the linear motor 10 and the table 13, and therecess 20 serving as a thermal insulating space is provided on the lowerside of the table 13 at a position between the thermal insulators 19.Accordingly, heat generated from the primary side 11 of the linear motor10 is prevented from being transferred to the table 13 by the heattransfer cutoff action of the thermal insulators 19 and the radiationheat blocking action of the recess 20. Therefore, there is no variationin the preload applied to the rolling elements arranged and accommodatedin the endless recirculation passages of the moving blocks 15.

In addition, because the inner surface of the recess 20 formed on thelower side of the table 13 is formed into a mirror finished surface, theradiation heat blocking effect is further improved.

FIGS. 8 to 10 are diagrams showing the arrangement of the guidemechanism 14 in detail. FIG. 8 is a perspective view. FIG. 9 is asectional view. FIG. 10 is a sectional view of a moving block.

Each rail 18 with a rectangular sectional configuration has two ballrolling grooves 18-1 formed on each of the right and left sides thereofas rolling element rolling surfaces extending along the longitudinaldirection of the rail 18. That is, a total of four ball rolling grooves18-1 are formed on each rail 18. Each moving block 15 has endlessrecirculation passages including load rolling grooves 15-1 forming loadrolling element rolling passages that face opposite the ball rollinggrooves 18-1. A plurality of balls 32 as rolling elements are arrangedand accommodated in the endless recirculation passages. The balls 32roll between the ball rolling grooves 18-1 and the corresponding loadrolling grooves 15-1 in response to the relative movement of the rail 18and the moving block 15. In this way, the balls 32 recirculate throughthe endless recirculation passages.

The guide mechanism 14 is arranged so as to be able to carry loadsapplied in all directions, i.e. moments in all directions, not tomention radial loads and horizontal loads.

Each moving block 15 comprises a moving block body 15 a and end caps 15b. The moving block body 15 a is formed with the load rolling grooves15-1 and ball return passages parallel to the respective load rollinggrooves 15-1. The end caps 15 b are connected to both ends,respectively, of the moving block body 15 a. Each end cap 15 b hasdirection change passages that connect the load rolling grooves 15-1 andthe ball return passages, respectively. The moving block 15 is mountedin such a manner as to sit astride the rail 18. The top of the movingblock 15 is arranged so that the table 13 is mounted and securedthereto.

The load rolling grooves 15-1 of the moving block 15 are formed facingopposite the respective ball rolling grooves 18-1 on the rail 18. Aplurality of balls 32, i.e. rolling elements, are put between the loadrolling grooves 15-1 and the ball rolling grooves 18-1.

As the moving block 15 moves, the balls 32 are fed into the ball returnpassages through the direction change passages formed in the end caps 15b and led to the load rolling grooves 15-1 again. In this way, the balls32 recirculate through the endless recirculation passages.

As shown in FIGS. 9 and 10, the plurality of balls 32 are rotatably andslidably retained in series by a retaining member 33. The retainingmember 33 comprises spacers 34 disposed alternately with the balls 32and a sheet-shaped flexible belt 35 connecting the spacers 34.

The balls 32 arranged and accommodated in the endless recirculationpassages are given a predetermined preload (contact pressure) to ensuresmooth rolling of the balls 32.

A seal member 36 is provided between the top of the rail 18 and themoving block 15. Seal members 37 are provided between the moving block15 and two sides of the rail 18. The seal members 36 and 37 preventleakage to the outside of a lubricant filled between the ball rollinggrooves 18-1 and the load rolling grooves 15-1 and also prevent entry ofdust from the outside.

FIG. 11 is a diagram showing schematically a structural example ofanother embodiment of the drive guide apparatus according to the presentinvention. In the figure, a cylindrical linear motor 50 comprises acylindrical primary side 51, which is an energized side includingarmature coils, and a secondary side 52 formed from a long columnarthrust shaft, which is a non-energized side.

A guide mechanism 53 has an outer rail 54 comprising a base portion 54-1and a pair of side walls 54-2 standing on both sides of the base portion54-1. The guide mechanism 53 further has an inner block 55 movable in agroove defined in a recess 58 that is formed between the side walls 54-2of the outer rail 54.

A table 56 is mounted on the inner block 55 of the guide mechanism 53.The table 56 has a longitudinal recess 58 formed in the center of thetop thereof. The linear motor 50 is attached to the table 56 throughthermal insulators 57.

In the drive guide apparatus arranged as stated above, if the thermalinsulators 57 are not interposed between the table 56 and the linearmotor 50, heat generated from the armature coils (not shown) of theprimary side 51 of the linear motor 50 when a driving electric currentis passed through the armature coils will be transferred to the innerblock 55 through the table 56, causing the inner block 55 to expandthermally.

The outer rail 54 has a plurality of rolling element rolling surfacesextending in the longitudinal direction thereof, as will be detailedlater. The inner block 55 is formed with endless recirculation passagesincluding load rolling element rolling passages corresponding to therolling element rolling surfaces.

A plurality of rolling elements (balls) are arranged and accommodated inthe endless recirculation passages so as to roll and recirculatetherethrough. Because the rolling elements have been given apredetermined preload, if the inner block 55 thermally expands, thepreload increases or decreases.

In this example, the thermal insulators 57 are interposed between thetable 56 and the linear motor 50. Therefore, heat generated from theprimary side 51 of the linear motor 50 is blocked by the thermalinsulators 57 from being transferred to the table 56 or the inner block55. Accordingly, the inner block 55 will not thermally expand. Thus,there is no variation in the preload applied to the plurality of rollingelements (balls) arranged and accommodated in the endless recirculationpassages as stated above.

The recess 58 formed in the center of the top of the table 56 acts as athermal insulating space that cuts off the transfer of radiation heatfrom the primary side 51. If the inner surface of the recess 58 isformed into a mirror finished surface, the effect of cutting off thetransfer of radiation heat is further improved.

It should be noted that reference numeral 59 denotes a cable socket forconnection with a power cable for supplying driving electric power tothe primary side 51 of the linear motor 50 and a signal cable for signaltransmission and reception.

FIG. 12 is a diagram showing a structural example of the guide mechanism53. As shown in the figure, the inner block 55 is movable in the groovein the recess 58 formed between the side walls 54-2 standing on bothsides of the base portion 54-1 of the outer rail 54.

The inner side surface of each side wall 54-2 has two ball rollinggrooves 54-3 formed as rolling element rolling surfaces along thelongitudinal direction of the outer rail 54.

Each outer side surface of the inner block 55 is formed with loadrolling grooves 55-1 as load rolling element rolling passagescorresponding to the ball rolling grooves 54-3 formed on the outer rail54. Balls 60 as rolling elements roll between the ball rolling grooves54-3 of the outer rail 54 and the load rolling grooves 55-1 of the innerblock 55 while carrying a load.

The inner block 55 has endless recirculation passages 55-2 for the balls60 in correspondence to the respective load rolling grooves 55-1. Byendlessly recirculating the balls 60 rolling along the load rollinggrooves 55-1, the inner block 55 moves along the outer rail 54.

A table 56 is secured to the top of the inner block 55, as stated above.The plurality of balls 60 arranged and accommodated in the endlessrecirculation passages 55-2 of the inner block 55 have been given apredetermined preload to ensure smooth rolling of the balls 60.

FIG. 13 is a diagram showing schematically a structural example of stillanother embodiment of the drive guide apparatus according to the presentinvention. In the figure, a cylindrical linear motor 70 comprises acylindrical primary side 71, which is an energized side includingarmature coils, and a secondary side 72 formed from a long columnarthrust shaft, which is a non-energized side.

Guide mechanisms 75 respectively comprise rails 77 provided on therespective upper end surfaces of side walls 78-2 standing on both sidesof a base portion 78-1. Moving blocks 76 are mounted in such a manner asto sit astride the rails 77, respectively.

The primary side 71 of the linear motor 70 is secured to a table 74through thermal insulators 73. The table 74 is secured to the movingblocks 76 of the guide mechanisms 75. A recess 79 acting as a thermalinsulating space is formed on the lower side of the table 74 at aposition between the thermal insulators 73.

When the armature coils (not shown) of the primary side 71 of the linearmotor 70 are supplied with an electric current, the primary side 71moves in the groove in the recess 79 formed between the side walls 78-2along the rails 77. Energization of the armature coils causes generationof heat from the primary side 71. However, the heat is blocked by thethermal insulators 73 from being transferred to the table 74. The recess79 formed on the lower side of the table 74 acts as a space for cuttingoff the transfer of radiation heat from the primary side 71 and thusblocks the radiation heat.

It should be noted that if the inner surface of the recess 79 is formedinto a mirror finished surface, the effect of cutting off the transferof radiation heat is further improved.

The arrangement of the guide mechanisms 75 is approximately the same asthat of the guide mechanism shown in FIGS. 8 to 10 (however, these guidemechanisms differ from each other in the number of rows of endlesslyrecirculating ball trains and in the layout thereof). Therefore, adescription thereof is omitted.

As has been stated above, the thermal insulators 73 are interposedbetween the primary side 71 of the linear motor 70 and the table 74, andthe recess 79 serving as a radiation heat blocking space is formed onthe lower side of the table 74. With this arrangement, heat generatedfrom the primary side 71 is prevented from being transferred to thetable 74. Consequently, thermal expansion of the table 74 will notoccur. Therefore, there is no variation in the preload applied to therolling elements arranged and accommodated in the endless recirculationpassages of the guide mechanisms 75.

In the above-described example, the thermal insulator is providedbetween the primary side of the linear motor and the moving block, thatis, the moving member, indirectly with the table, etc. interposedtherebetween. It should be noted, however, that the thermal insulatormay be interposed directly between the primary side of the linear motorand the moving block. In addition, although in the above-describedexample the thermal insulating means is interposed between the primaryside of the linear motor and the moving member, the thermal insulatingmeans may be provided between the primary side of the linear motor andthe track (rail) to prevent heat generated from the primary side frombeing transferred to the rail.

Incidentally, the guide mechanism for guiding the primary side and thesecondary side of the linear motor in the foregoing examples employs arolling guide arrangement in which the rail (rails 18 and outer rail 54)and the moving block (moving blocks 15 and inner block 55) are movablerelative to each other through the rolling elements (balls or rollers)interposed therebetween. However, the present invention is not limitedto the rolling guide arrangement but may employ a slide guidearrangement.

FIG. 14 is a diagram showing schematically a structural example of adrive guide apparatus having a slide guide mechanism 84. This driveguide apparatus is arranged in the same way as the drive guide apparatusaccording to the first embodiment shown in FIG. 2 except the followingarrangement.

As shown in the figure, a pair of guide mechanisms 84 are respectivelyprovided on the right and left sides of the base 16. Each guidemechanism 84 has a rail 88 with a rectangular sectional configurationand a moving block 85 mounted astride the rail 88 in such a manner as tobe movable relative to the rail 88. The table 13 is fitted to the uppersides of the moving blocks 85. The rails 88 and the moving blocks 85 areslidably assembled together directly with no rolling elements interposedtherebetween to form a slide guide.

More specifically, assuming that the mutually opposing surfaces of therails 88 of the two guide mechanisms 84 are inner surfaces, a gap e isformed between the outer surface of each rail 88 and the outer legportion 85-1 of the associated moving block 85. That is, the two rails88 are in sliding contact with the associated moving blocks 85 at theirinner and upper surfaces. Further, a predetermined surface pressure isproduced between the inner surface of each rail 88 and the inner legportion 85-2 of the associated moving block 85.

In this drive guide apparatus also, the thermal insulator 19 is providedbetween the primary side 11 of the linear motor 10 and the table 13.Thus, heat generated from the armature coils (not shown) of the primaryside 11 when a driving electric current is passed through the armaturecoils is prevented from being transferred to the table 13 or the movingblocks 85. Accordingly, neither the table 13 nor the moving blocks 85will thermally expand. Therefore, sliding resistance between the rails88 and the moving blocks 85 is prevented from varying and kept constant.Thus, it is possible to ensure an increased lifetime for the drive guideapparatus.

FIG. 15 is a diagram showing schematically the arrangement of anotherdrive guide apparatus having a slide guide mechanism. This drive guideapparatus is arranged in the same way as the drive guide apparatus shownin FIG. 14 except the following arrangement.

As illustrated in the figure, assuming that the mutually opposingsurfaces of the rails 88 of two guide mechanisms 84 provided on theright and left sides are inner surfaces, a gap e is formed between theinner surface of each rail 88 and the inner leg portion 85-2 of theassociated moving block 85. That is, the two rails 88 are in slidingcontact with the associated moving blocks 85 at their outer and uppersurfaces. Further, a predetermined surface pressure is applied betweenthe outer surface of each rail 88 and the outer leg portion 85-1 of theassociated moving block 85.

In this drive guide apparatus also, the transfer of heat generated fromthe armature coils of the primary side 11 of the linear motor 10 is cutoff by the thermal insulator 19 in the same way as in the drive guideapparatus shown in FIG. 14. Accordingly, neither the table 13 nor themoving blocks 85 will thermally expand. Therefore, sliding resistancebetween the rails 88 and the moving blocks 85 is prevented from varying.Thus, it is possible to ensure an increased lifetime for the drive guideapparatus.

FIG. 16 shows schematically the arrangement of still another drive guideapparatus having a slide guide mechanism. This drive guide apparatus isarranged in the same way as the drive guide apparatus shown in FIGS. 14and 15 except the following arrangement.

In this drive guide apparatus, as shown in the figure, the rail 88 ofone of the two guide mechanisms 84 provided on the right and left sides,i.e. the right guide mechanism 84 in the illustrated example, has gaps eformed respectively between the inner and outer surfaces thereof and theinner and outer leg portions 85-1 and 85-2 of the associated movingblock 85. In other words, the rail 88 is in sliding contact with themoving block 85 only at the upper surface thereof.

The rail 88 of the other, or left guide mechanism 84 is in slidingcontact with the associated moving block 85 at the inner and uppersurface thereof. The outer surface of the rail 88 is in engagement withthe inner leg portion 85-2 of the moving block 85 through a gib 89. Inother words, a predetermined surface pressure is applied between theouter surface of the rail 88 and the outer leg portion 85-1 of theassociated moving block 85. In addition, a predetermined surfacepressure is applied between the inner surface of the rail 88 and theinner leg portion 85-2 of the moving block 85.

In this drive guide apparatus also, the transfer of heat generated fromthe armature coils of the primary side 11 of the linear motor 10 is cutoff by the thermal insulator 19 in the same way as in the drive guideapparatus shown in FIGS. 14 and 15. Accordingly, neither the table 13nor the moving blocks 85 will thermally expand. Therefore, slidingresistance between the rails 88 and the moving blocks 85 is preventedfrom varying. Thus, it is possible to ensure an increased lifetime forthe drive guide apparatus.

FIGS. 17 and 18 are graphs showing the results of temperature-rise testsperformed on the drive guide apparatus arranged as shown in FIG. 11. Inthe graphs, the abscissa axis represents the elapsed time (h (hour)),and the ordinate axis represents the rise in temperature (° C.).Temperature measurement points are a point P1 on the linear motor 50 anda point P2 on the inner block 55. In a state where the travel of theprimary side 51 as the energized side of the linear motor 50 wassuspended (retrained), the primary side 51 was supplied with an electriccurrent to measure a rise in temperature thereof.

FIGS. 17 and 18 show examples of temperature-rise tests performed onlinear motors 50 different in ratings from each other. FIGS. 17 and 18show the results of temperature-rise tests in which a rated peak currentof 2.86 A and a rated peak current of 2.96 A were supplied to theprimary sides 51 of the linear motors 50, respectively.

In the example of FIG. 17, the temperature at the point P1 on the linearmotor 50 rises to 63.0° C., whereas the temperature at the point P2 onthe inner block 55 rises only to 10.2° C. Thus, the graph shows aremarkable thermal insulating effect produced by providing the thermalinsulators 57 between the table 56 and the linear motor 50 and furtherforming a space defined by the recess 58 in the center of the top of thetable 56.

In the example of FIG. 18, the temperature at the point P1 on the linearmotor 50 rises to 57.2° C., whereas the temperature at the point P2 onthe inner block 55 rises only to 8.9° C. Thus, the graph shows aremarkable thermal insulating effect produced by providing the thermalinsulators 57 between the table 56 and the linear motor 50 and furtherforming a space defined by the recess 58 in the center of the top of thetable 56.

FIGS. 19 and 20 are graphs showing the results of temperature-rise testsperformed on the drive guide apparatus arranged as shown in FIG. 13. Inthe graphs, the abscissa axis represents the elapsed time (h), and theordinate axis represents the rise in temperature (° C.). Temperaturemeasurement points are a point P3 on the linear motor 70 and a point P4on the top of the table 74. In a state where the travel of the primaryside 71 as the energized side of the linear motor 70 was suspended(retrained), the primary side (armature coils) 51 was supplied with anelectric current to measure a rise in temperature thereof.

FIGS. 19 and 20 show examples of temperature-rise tests performed onlinear motors 70 different in ratings from each other. FIGS. 19 and 20show the results of temperature-rise tests in which a rated peak currentof 2.34 A and a rated peak current of 2.23 A were supplied to theprimary sides 71 of the linear motors 70, respectively.

In the example of FIG. 19, the temperature at the point P3 on the linearmotor 70 rises to 58.7° C., whereas the temperature at the point P4 onthe table 74 rises only to 8.2° C. Thus, the graph shows a remarkablethermal insulating effect produced by providing the thermal insulators73 between the table 74 and the linear motor 70 and further forming aspace defined by the recess 79 in the center of the lower side of thetable 74.

In the example of FIG. 20, the temperature at the point P3 on the linearmotor 70 rises to 65.1° C., whereas the temperature at the point P4 onthe table 74 rises only to 13.0° C. Thus, the graph shows a remarkablethermal insulating effect produced by providing the thermal insulators73 between the table 74 and the linear motor 70 and further forming aspace defined by the recess 79 in the center of the lower side of thetable 74.

As has been stated above, a thermal insulating effect is produced byproviding a thermal insulator and a space for blocking heat generatedfrom the primary side of the linear motor between the primary side andthe rail or the moving member of the guide mechanism to which theprimary side of the linear motor is connected. However, to furtherimprove the thermal insulating effect (heat dissipation effect), amultiplicity of fins 70 a may be provided on the outer surfaces of thelinear motor 70, as shown in FIG. 21. It should be noted that the driveguide apparatus shown in FIG. 21 is the same as the drive guideapparatus shown in FIG. 13 except that a multiplicity of fins 70 a areprovided on the outer surfaces of the linear motor 70. The operation ofthe drive guide apparatus shown in FIG. 21 is the same as that of thedrive guide apparatus shown in FIG. 13.

FIG. 22 is a diagram showing a specific structural example of the driveguide apparatus according to the present invention. The drive guideapparatus is approximately the same as the drive guide apparatus shownin FIGS. 4 to 7 in terms of the arrangement of the main body partthereof but differs from the latter in the structure of the linear motorand in the arrangement for dissipating heat from the heat generatingpart of the linear motor. That is, a linear motor 10′ of the drive guideapparatus has a secondary side (stationary side) 12′ formed with aU-shaped sectional configuration. The primary side (moving side) 11′ ofthe linear motor 10′ has a plate-shaped configuration. The primary side11′ is movable through a groove with a U-shaped sectional configurationdefined in the secondary side 12′.

The primary side 11′ has a finned heatsink 40 secured theretointegrally. The heatsink 40 has a multiplicity of radiating fins 41. Atable 13 is provided over the finned heatsink 40 with thermal insulators19 interposed therebetween.

In the drive guide apparatus arranged as stated above, when a drivingelectric current is passed through the armature coils (not shown) of theprimary side 11′, the table 13, which is secured to the primary side 11′with the finned heatsink 40 and the thermal insulators 19 interposedtherebetween, moves in response to driving force from the primary side11′ while being guided by the guide mechanisms 14. That is, the table 13secured to the moving blocks 15 moves along the rails 18.

Thus, the linear motor 10′ is arranged such that the plate-shapedprimary side 11′ moves through the groove in the secondary side 12′formed with a U-shaped sectional configuration. With this arrangement,the primary side (armature coils) 11′ is surrounded by the secondaryside (consisting essentially of magnets) 12′. Therefore, dissipation ofheat generated from the primary side 11′ is prevented.

In this example, the finned heatsink 40 is integrally secured to theprimary side 11′, as stated above. Therefore, heat generated from theprimary side 11′ is transferred to the finned heatsink 40 andefficiently dissipated from the radiating fins 41.

The finned heatsink 40 employs an already-known arrangement in which aheat pipe is provided in the heatsink 40, for example. By attaching thefinned heatsink 40 to the primary side 11′ of the linear motor 10′ asstated above, heat generated from the primary side 11′ is dissipatedefficiently even in the case of the linear motor 10′ having anarrangement in which the primary side 11′ is surrounded by the secondaryside (magnets) 12′ and hence the heat dissipation effect is not good.Thus, it becomes possible to minimize the rise in temperature of thelinear motor 10′.

Further, because the thermal insulators 19 are interposed between thefinned heatsink 40 and the table 13, the transfer of heat to the table13 or the moving blocks 15 is further retarded.

FIG. 23 is a diagram showing a structural example of a radiating finplate of the above-described finned heatsink. FIG. 24 is an enlargedview of a radiating fin.

The radiating fin plate has a structure in which a multiplicity of longplate-shaped radiating fins 41 are stood at predetermined intervals onthe top of a base plate 42. As shown in FIG. 24, each individualradiating fin 41 has corrugations 41a provided on both sides thereof.With this arrangement, the heat radiation area of each individualradiating fin 41 is increased.

FIG. 25 is a diagram showing a specific structural example of the driveguide apparatus according to the present invention. The illustrateddrive guide apparatus is approximately the same as the drive guideapparatus shown in FIG. 22 in terms of the arrangement. The drive guideapparatus differs from the latter in the material constituting thethermal insulators 19 interposed between the table 13 and the finnedheatsink 40 and in the structure for connecting together the table 13and the finned heatsink 40.

The thermal insulators 19 in this example absorb a deformation of thefinned heatsink 40 due to thermal expansion to prevent deformation ofthe primary side (moving element) 11′ of the linear motor 10′ that isconnected to the finned heatsink 40.

Because the finned heatsink 40 is secured to the table 13, when itthermally expands, the finned heatsink 40 is curvedly deformed owing toa thermal expansion difference therebetween.

The deformation of the finned heatsink 40 causes the primary side(moving element) 11′ of the linear motor 10′ to be displaced.Consequently, the gap between the primary side 11′ and the secondaryside (stator) 12′ changes. This exerts an influence upon thecharacteristics of the linear motor 10′.

In this example, when the finned heatsink 40 thermally expands in thedirections shown by the double-headed arrow B in FIG. 26A, shearingforce acts on the thermal insulators 19 at both sides of the finnedheatsink 40. In such a case, the thermal insulators 19 are deformed asshown in FIG. 26B, thereby absorbing the deformation of the finnedheatsink 40 due to the thermal expansion. That is, the thermalinsulators 19 are deformed from the shape shown in (a) of FIG. 27 to therespective shapes as shown in (b) and (c) of FIG. 27, thereby absorbingthe deformation of the finned heatsink 40.

Thus, the deformation of the finned heatsink 40 disappears. Therefore,there is no change in the gap dimension between the primary side 11′ andthe secondary side (stator) 12′ of the linear motor 10′. Accordingly, noinfluence is exerted upon the characteristics of the linear motor 10′.For the thermal insulators 19, a material that has excellent thermalinsulating properties and that is easily deformable by shearing force(i.e. a material easy to deform in the width direction and rigid in thethickness direction) is used. For example, a laminated glass-epoxy resinmaterial is suitably used for the thermal insulators 19 because it isexcellent in thermal insulating performance and easily deformable byshearing force.

The finned heatsink 40 is fastened to the table 13 with the thermalinsulators 19 interposed therebetween by using bolts 43. FIG. 28 is adiagram showing a fastening structure using bolts 43.

As shown in the figure, a spot-faced hole 13 a is provided in a portionof the top of the table 13 at which a bolt 43 extends through the table13. The spot-faced hole 13 a has a flanged cylindrical member 44 and awasher 45 inserted therein. The bolt 43 extends through the flangedcylindrical member 44 and the washer 45 and engages a threaded hole 46provided in the finned heatsink 40. That is, the finned heatsink 40 isfastened to the table 13 with the bolts 43 in a state where the thermalinsulators 19 are interposed between the finned heatsink 40 and thetable 13 and the flange of the cylindrical member 44 and the washer 45are interposed between the head 43 a of the bolt 43 and the table 13.

The finned heatsink 40 is fastened at both sides thereof with the samefastening structure using the bolts 43. It should be noted that a gap 49is provided between the outer peripheral portion of the bolt 43 and theinner wall surface of a bolt receiving hole 13 b to prevent heat fromthe finned heatsink 40 from being transferred to the table 13 from theouter peripheral portion of the bolt 43.

The flanged cylindrical member 44 uses a material excellent in thermalinsulating performance and easily deformable by shearing force (e.g.laminated glass-epoxy resin material) as in the case of the thermalinsulators 19. Thus, when the finned heatsink 40 thermally expands owingto a rise in temperature, the thermal expansion of the finned heatsink40 is absorbed by deformation of the thermal insulators 19 as statedabove and further by deformation of the flanged cylindrical members 44from the shape shown in (a) of FIG. 29 to the respective shapes as shownin (b) and (c) of FIG. 29. Accordingly, the finned heatsink 40 will notbe curvedly deformed even if it thermally expands owing to a rise intemperature.

Although heat from the finned heatsink 40 is transferred to the bolts43, there is no possibility of the heat being transferred to the table13 because the flanged cylindrical members 44, which are excellent inthermal insulating performance, are interposed between the bolts 43 andthe table 13.

In this drive guide apparatus, as shown in FIG. 25, a heatsink 47 isattached to an end portion of the primary side of the linear motor 10′.As shown in FIG. 30, the heatsink 47 has a U-shaped sectionalconfiguration. One wall of the U-shaped structure of the heatsink 47 isprovided with a multiplicity of slits 47 a at predetermined intervals,thereby providing radiating fins 48. The effect of dissipating heat fromthe primary side of the linear motor 10′ is further improved byproviding the heatsink 47 arranged as stated above on the end portion ofthe primary side of the linear motor 10′.

INDUSTRIAL APPLICABILITY

As has been stated above, according to the invention recited in claim 1,thermal insulating means for blocking heat generated from the primaryside of the linear motor is provided between the primary side of thelinear motor and the rail or the moving member of the guide mechanism towhich the primary side of the linear motor is connected. Therefore, heatgenerated from the primary side of the linear motor is prevented frombeing transferred to the rail or the moving member of the guidemechanism. Consequently, thermal expansion of the rail or the movingmember is prevented, and there is no variation in rolling resistance orsliding resistance of the guide mechanism. Accordingly, it is possibleto ensure an increased lifetime for the drive guide apparatus.

According to the invention recited in claim 2, the thermal insulatingmeans comprises a thermal insulator interposed between the rail or themoving member and the primary side of the linear motor. Thus, anincreased lifetime can be ensured for the drive guide apparatus with asimple arrangement.

According to the invention recited in claim 3, the thermal insulator iselongated in the direction of relative movement between the rail and themoving member. By doing so, rigidity in this direction increases. Thus,undesired oscillation phenomena can be prevented.

According to the invention recited in claim 4, the thermal insulatingmeans comprises a thermal insulating space formed between the rail orthe moving member and the primary side of the linear motor. With thisarrangement, it is possible to cut off the transfer of radiation heatfrom the primary side of the linear motor. Therefore, it is possible toprevent thermal expansion of the rail or the moving member due toradiation heat and hence possible to eliminate variation in rollingresistance or sliding resistance of the guide mechanism. Accordingly, anincreased lifetime can be ensured for the drive guide apparatus as inthe case of the above.

According to the invention recited in claim 5, the thermal insulatingspace has a mirror finished surface at a side thereof closer to the railor the moving member of the guide mechanism to which the primary side ofthe linear motor is connected. With this arrangement, the transfer ofradiation heat from the primary side of the linear motor can be cut offeven more effectively.

According to the invention recited in claim 6, the guide mechanism isarranged in the form of a rolling guide. That is, the rail is formedwith a rolling element rolling surface extending longitudinally of therail. The moving member has an endless recirculation passage including aload rolling element rolling passage corresponding to the rollingelement rolling surface. A multiplicity of rolling elements are arrangedand accommodated in the endless recirculation passage. The rollingelements recirculate through the endless recirculation passage whilereceiving a load in the load rolling element rolling passage. In therolling guide according to this invention, the preload applied to therolling elements is not varied by a stress generated by thermalexpansion of the rail or the moving member. Accordingly, smooth rollingof the rolling elements is ensured, so that an increased lifetime of thedrive guide apparatus is attained. In the rolling guide, if the preloadincreases, flaking (a phenomenon in which the surface of the racewaysurface or the rolling element surface peels off in flakes owing to therolling fatigue of the material) is likely to occur. If flaking occurs,the lifetime reduces markedly.

According to the invention recited in claim 7, a heatsink is provided todissipate heat generated from the primary side of the linear motor. Withthis arrangement, heat generated from the primary side of the linearmotor can be dissipated efficiently. Therefore, the transfer of the heatto the rail or the moving member of the guide mechanism is furtherretarded. As a result, restrictions on the linear motor configurationfor heat dissipation are reduced. Accordingly, it is possible to employa linear motor having an arrangement even more suitable for the driveguide apparatus.

According to the invention recited in claim 8, the heatsink is a finnedheatsink having radiating fins. By using the finned heatsink, the heatdissipation effect is further enhanced. Accordingly, the transfer ofheat to the rail or the moving member of the guide mechanism is furtherretarded.

According to the invention recited in claim 9, when the heatsink isthermally expanded and deformed by heat from the primary side of thelinear motor, shearing force acts on the absorbing member. Consequently,the absorbing member is shear-deformed to absorb the deformation of theheatsink. Therefore, the heatsink is not deformed, and the primary sideof the linear motor is not displaced. Accordingly, there is no change inthe gap between the primary side and the secondary side of the linearmotor. Hence, there is no change in characteristics of the linear motor.

According to the invention recited in claim 10, the absorbing member hasboth the function of absorbing a deformation of the heatsink by sheardeformation and the thermal insulating function of cutting off the heattransfer from the heatsink to the moving member. Therefore, no influenceis exerted upon the characteristics of the linear motor as stated above.Moreover, there is no variation in rolling resistance or slidingresistance of the guide mechanism. Accordingly, it is possible to ensurean increased lifetime for the drive guide apparatus.

According to the invention recited in claim 11, a laminated glass-epoxyresin material is used for the absorbing member. By doing so, adeformation of the heatsink is absorbed easily. That is, the laminatedglass-epoxy resin material exhibits strong rigidity in the laminationdirection (thickness direction) and weak rigidity in a direction (widthdirection) perpendicular to the lamination direction. Therefore, whenthe heatsink thermally expands in response to a rise in temperature,shearing force acts on the absorbing member. At this time, the absorbingmember is easily deformed to absorb the deformation of the heatsink.Accordingly, it is possible to ensure an increased lifetime for thedrive guide apparatus.

1. A drive guide apparatus having a linear motor and a guide mechanismthat guides relative movement between a primary side of said linearmotor, which is an energized side thereof, and a secondary side of saidlinear motor, which is a non-energized side thereof, and that carries aload, said guide mechanism having a rail and a moving member provided tobe movable relative to said rail, the primary side of said linear motorbeing connected directly or indirectly to the rail or the moving memberof said guide mechanism, wherein thermal insulating means for blockingheat generated from the primary side of said linear motor is providedbetween said primary side and the rail or the moving member of saidguide mechanism to which said primary side is connected, wherein aheatsink that dissipates heat generated from the primary side of saidlinear motor is provided.
 2. A drive guide apparatus according to claim1, wherein said heatsink is a finned heatsink having radiating fins.